Hi,
I had a spawn 2 weeks ago,everything went fine.
I have some fry that are swimming in a zig-zag pattern.
They will swim to the top and then fall to the bottom,they also swim around the tank in the zig-zag pattern,fast,but just wierd.
Could this be just a birth type problem?
I breed in a 10 gal tank,with AL,a corner foam filter(the filter is turned down to just a couple of bubbles now and again.
I have the tank filled to about 4-5 inches,no problem untill they turned 2 weeks old.
Thanks
Bill

HI Bill, there must be something wrong with your fry. They shouldn't fall to the bottom (after 2 weeks). But they often swim and stay at the bottom. Nor should they zig zag - they would sometimes dash and "disappear". Unfortunately I don't know what the problem might be as a number of things might influence their development - genetic, water parameters, humidity, food, or disease.

Maybe try a massive water change (70 - 90%) and refill very slowly. This should in the least reduce water related issues.